1. Field of the Invention
The present invention relates to a display device.
2. Description of the Related Art
In a liquid crystal display, a color image is displayed in such a manner that a liquid crystal shutter is provided to each pixel, a color filter is provided to each pixel, and light irradiated from a white-color backlight light source arranged behind the pixel is allowed to selectively pass through the liquid crystal shutter and the color filter. However, the liquid crystal display has a drawback that a fine working process is necessary for acquiring high definition. This is because it is necessary to provide three pixels corresponding to three colors of R (red), G (green) and B (blue) of a color filter for every pixel to realize a color image. In a single plate color projector or the like, it is unnecessary to provide such three pixels. That is, the single plate color projector or the like adopts a so-called field sequential display method where irradiation lights of three colors of R, G, B are sequentially generated using a color filter rotary disc, and the irradiation lights are modulated by pixels using liquid crystal, an MEMS (Micro Electro Mechanical System) shutter or the like thus sequentially generating an image of three colors.
However, it has been known that this field sequential display method has a drawback referred to as color decomposition where three colors of R, G and B are visually recognized in a decomposed manner when a moving image is displayed. Although the color decomposition is also expressed as color break up, color splitting or the like, the expression “color decomposition” is used throughout this specification.
With respect to a means for overcoming this color decomposition, a first prior art is explained in conjunction with FIG. 32. FIG. 32 is a schematic view of a moving image display in the first prior art, wherein an X coordinate on a screen is taken on an axis of abscissas and time is taken on an axis of ordinates, and the manner that a white image displayed in accordance with a field sequential method moves in the X direction is expressed. In this prior art, to obviate the color decomposition which generates particular coloring in front of and behind the white moving image, lights of R, G, B are emitted in different order for every 1 frame. This prior art is described in detail in Japanese Patent Application Publication JP 8-248381 A and JP 2002-223453 A.
FIG. 34 shows a timing chart of light emitting brightness of a light source used in a field sequential method of a second prior art where time is taken on an axis of abscissas and brightness is taken on an axis of ordinates. In this prior art, to increase a speed of lighting frequency of each color thus obviating color decomposition, a light of additional color is further emitted for every 1 frame. In FIG. 34, a light emitting cycle completes one turn for every three frames and hence, for the sake of convenience, a frame where a light of R (red) is emitted twice is set as a first frame, and frames where a light of G (green) and a light of B (blue) are emitted twice are set as a second frame and a third frame respectively. This placement is explained again later in conjunction with the explanation of a graph shown in FIG. 35. This prior art is described in detail in a second embodiment of the invention described in JP 2007-206698 A.